fix resampling leads to Hard to tap (#81022)

* fix PointerUpEvent conversion PointerMoveEvent needs to use the default buttons value.(#73286)

* feat PointerMoveEvent conversion adds test cases

* fix event conversion may modify the original buttons value.

* Update packages/flutter/lib/src/gestures/resampler.dart
Co-authored-by: David Reveman <dreveman@gmail.com>

packages/flutter/lib/src/gestures/resampler.dart

@@ -42,12 +42,14 @@ class PointerEventResampler {
   bool _isTracked = false;
   bool _isDown = false;
   int _pointerIdentifier = 0;
+  int _hasButtons = 0;
 
   PointerEvent _toHoverEvent(
     PointerEvent event,
     Offset position,
     Offset delta,
     Duration timeStamp,
+    int buttons,
   ) {
     return PointerHoverEvent(
       timeStamp: timeStamp,
@@ -79,6 +81,7 @@ class PointerEventResampler {
     Offset delta,
     int pointerIdentifier,
     Duration timeStamp,
+    int buttons,
   ) {
     return PointerMoveEvent(
       timeStamp: timeStamp,
@@ -87,7 +90,7 @@ class PointerEventResampler {
       device: event.device,
       position: position,
       delta: delta,
-      buttons: event.buttons,
+      buttons: buttons,
       obscured: event.obscured,
       pressure: event.pressure,
       pressureMin: event.pressureMin,
@@ -113,9 +116,12 @@ class PointerEventResampler {
     int pointerIdentifier,
     Duration timeStamp,
     bool isDown,
+    int buttons,
   ) {
-    return isDown ? _toMoveEvent(event, position, delta, pointerIdentifier, timeStamp)
-                  : _toHoverEvent(event, position, delta, timeStamp);
+    return isDown
+        ? _toMoveEvent(
+            event, position, delta, pointerIdentifier, timeStamp, buttons)
+        : _toHoverEvent(event, position, delta, timeStamp, buttons);
   }
 
   Offset _positionAt(Duration sampleTime) {
@@ -205,10 +211,12 @@ class PointerEventResampler {
 
       final bool wasTracked = _isTracked;
       final bool wasDown = _isDown;
+      final int hadButtons = _hasButtons;
 
       // Update pointer state.
       _isTracked = event is! PointerRemovedEvent;
       _isDown = event.down;
+      _hasButtons = event.buttons;
 
       // Position at `sampleTime`.
       final Offset position = _positionAt(sampleTime);
@@ -235,7 +243,8 @@ class PointerEventResampler {
         // therefor never produce `hover` events.
         if (position != _position) {
           final Offset delta = position - _position;
-          callback(_toMoveOrHoverEvent(event, position, delta, _pointerIdentifier, sampleTime, wasDown));
+          callback(_toMoveOrHoverEvent(event, position, delta,
+              _pointerIdentifier, sampleTime, wasDown, hadButtons));
           _position = position;
         }
         callback(event.copyWith(
@@ -261,7 +270,8 @@ class PointerEventResampler {
     final PointerEvent? next = _next;
     if (position != _position && next != null) {
       final Offset delta = position - _position;
-      callback(_toMoveOrHoverEvent(next, position, delta, _pointerIdentifier, sampleTime, _isDown));
+      callback(_toMoveOrHoverEvent(next, position, delta, _pointerIdentifier,
+          sampleTime, _isDown, _hasButtons));
       _position = position;
     }
   }

packages/flutter/test/gestures/resampler_test.dart

@@ -153,6 +153,8 @@ void main() {
     expect(result[4].position.dy, 15.0);
     expect(result[4].delta.dx, 10.0);
     expect(result[4].delta.dy, -10.0);
+    // buttons field needs to be a valid value
+    expect(result[4].buttons, kPrimaryButton);
     expect(result[5].timeStamp, const Duration(microseconds: 4500));
     expect(result[5] is PointerUpEvent, true);
     expect(result[5].position.dx, 35.0);